The Long Term Evolution (LTE) developed by the 3rd Generation mobile communication Partnership Project (3GPP) is intended to provide increasingly diversified mobile services, and encompasses a packetizing voice communication standard. The first edition (i.e. Release 8) of the LTE by the 3GPP employs the orthogonal frequency-division multiple access (OFDMA) technology and the multiple-antenna (MIMO) technology. In addition, Release 10 developed by the 3GPP has been evaluated and measured by the International Telecommunication Union, and has then been officially designated as a 4th generation global mobile communication standard; LTE-Advanced. The LTE-Advanced standard employs carrier aggregation (CA) and a relay technology. This has realized the enhancement of uplink/downlink MIMO technology and support for Het-Net setting.
For increase in energy use efficiency of an LTE-Advanced system and for improvement in spectral efficiency, the 3GPP has decided to introduce a new carrier type (NCT) into the current edition (Release 11) of LTE. The introduction will be carried out mainly in two stages. In the first stage, NCT is normalized mainly by synchronizing carriers within a CA frame and by reducing cell-specific reference signals (CRS) and control channels in the NCT. In the second stage, NCT processing in a stand-alone mode is realized. Specifically, a mobile communication service and data processing are provided while only a NCT carrier is present with respect to one or a plurality of service cells in a cellular system.
The NCT processing during the stand-alone mode mainly relates to (i) a broadcast mechanism of system information on a service cell, (ii) acquisition of a common search space (CSS) of an enhanced physical downlink control channel (ePDCCH), and support for user equipment (UE) mobility. Furthermore, it is necessary to consider also other functions of future LTE, such as Coordinated Multipoint (CoMP).